When comparing Duality vs RPG Maker, the Slant community recommends Duality for most people. In the question“What are the best 2D game engines?”Duality is ranked 25th while RPG Maker is ranked 28th. The most important reason people chose Duality is:

The full source code is available on GitHub, where the framework is actively developed. All of the editor, core and plugin code is written in C#.

Pros

Pro

Open source

The full source code is available on GitHub, where the framework is actively developed. All of the editor, core and plugin code is written in C#.

Pro

Great editor

Duality includes a powerful visual editing system that can be used for previewing, integrating, editing and testing game content.

Pro

Live reload of code and assets

Pro

Very extensible

Because both Core and Editor are completely plugin-based, Duality not only incorporates a clean and modular design, but is also very extensible - even if it wasn't Open Source. In fact, most of the standard editing capabilities comes in form of Editor plugins.

Pro

Built-in physics and lighting

Pro

Friendly to version control systems

It can be configured to serialize all data in a text-based format, which has been structurally optimized for version control systems.

Pro

Used in commercial projects

It has been used in a production environment without burning the place to the ground. Supposedly artist-proof editor workflow with an API for tailoring the system to fit your team.

Pro

Easy to jump into using an intuitive WYSIWYG editor

It's possible to create a game with absolutely no art or coding skills, so even complete beginners can make something.

Pro

Large and active community

The engine has seen multiple iterations since 1995, so a large online community exists that is always willing to help each other out.

Pro

Ruby / Javascript support provides depth to more experienced developers

With a script editor that uses a modified version of Ruby, it's possible to go well beyond the traditional RPG with this engine. Note: XP and VX use Ruby, the latest version "MV" uses Javascript for scripting.

Pro

A cheap license that allows using the software commercially

There are several versions of RPG maker, with MV being the latest and most fully featured: MV ($79.99), VX Ace ($69.99), VX ($59.99) and XP ($24.99), 2003 ($19.99).

Pro

Greater Map layers

MV Mapping uses an additional layer to create better depth.

Pro

Multi-platform

MV supports HTML5 exports, so it is easier than ever to make your game work on iOS, android, OSX,Linux or Windows.

Pro

MV has HTML5 export

You can now HTML5 export your projects, so you could theoretically host your game on your webserver, and have your friends play the game without ever having to install a single thing.